Computer generated 3-D modeling and animation enrich a wide range of human experiences that includes everything from captivating audiences at the movie theaters, to gluing garners to their video games, to embarking home buyers on virtual tours of new homes. To generate a 3-D animation, a designer interacts with a 3-D modeling program, such 3D Studio Max™, which is commercially available from Autodesk, Inc., to create a set of animation sequences for importing into a computer graphic application, such as a game engine or computer animated movie. Conventionally, in developing an animation sequence, the designer interacts with the modeling program to generate a set of “short” cycles that can then be used to simulate the various motions of the objects that are to be used within a scene. For example, to simulate a person walking, the designer can create a set of snapshot images that depict a single cycle of the person walking (“walk cycle”). The walk cycle can then be repeated multiple times to generate an animation sequence that simulates the person walking.
In general, to facilitate the simulation of a complex animation sequence a designer is required to generate numerous short cycles in which multiple objects are required to interact and simultaneously move in concert with one another. Conventionally, to generate a short cycle, the designer is required to individually move and/or adjust each object for each snapshot that is to be included within the cycle. For example, to create a cycle that simulates a person speaking, the designer must individually adjust each facial attribute (for example, the eyes, mouth, nose, ears, eyebrows, etc.) to produce the different facial expressions that are required for an animation sequence.
To aid in the creation of short cycles, it is often desirable to establish a relationship between attributes of objects that are to be included within an animation sequence. By establishing these relationships, the designer can be guaranteed that certain objects are correctly synchronized with each other, thus allowing the designer to create a more realistic animation sequence while reducing the amount effort and time that is required to generate the sequence. For example, to create an animation sequence that simulates a person speaking, certain facial attributes (for example, the eyes, mouth, nose, ears, eyebrows, etc.) may be linked to a slider and/or dial (“manipulator”). Thereafter, by simply adjusting the position of the manipulator, the designer can cause the facial attributes to simultaneously move in concert so as to provide both realistic and repeatable facial expressions.
However, a drawback with conventional modeling programs is the values that are associated with the various object attributes are not typically exposed to the animation designer. Thus, in order to establish a relationship between multiple object attributes, a technical director is required to generate program code defines the desired relationships and/or links for the object attributes.
Based on the foregoing, there is a clear need for a mechanism that allows relationships to be easily established between multiple object attributes for aiding in the generation of animation sequences.